There is a boycott by the Big 10 and the SEC against ND. They will not schedule ND in October and November. This has been an ongoing thing since the 1920s, and it has nothing to do with the teams not wanting to interrupt their conference schedules. Their motive has always been to prevent ND from being successful. Sure there have been exceptions, like Alabama in 1976 and 1987, and Ohio State on 1995 and 1996, and LSU a Tenn a couple of times, but they are few and far between. And ND had to pull teeth and give financial incentives to make these few games happen.
And now, with the bigger TV contract money, the conference cartels want to suck the life out of ND by forcing us into the Big 10 or a super-conference under less than favorable TV revenue sharing. That’s the real reason USC backed out of renewing ND.
I bet the series with Florida will be cancelled or moved to September, and it is the only SEC or Big 10 games in Oct-Nov on the schedule for the next several years. The contract with the ACC was Swarbricks response to this, but the best response would be a lawsuit claiming Anti-Trust violations.